1. Field of the Invention
The present invention relates to a small-sized imaging device which detects position information and image information.
2. Description of the Related Art
A substrate inspection apparatus inspects the surface of a semiconductor wafer and detects a defect if present.
The defect is specifically a scratch, a chipped portion, an uneven surface portion, a stain, or dust.
The substrate inspection apparatus performs two kinds of inspection: macro inspection wherein the semiconductor wafer is visually observed, and micro inspection wherein the surface of the semiconductor wafer is inspected by examining the surface in an enlarged scale by use of a microscope.
The substrate inspection apparatus includes a wafer carrier in which a plurality of semiconductor wafers are housed, an inspection section which performs the macro inspection and micro inspection, and a loader section which takes a semiconductor wafer out of the wafer carrier and delivers it to the inspection section and which receives an inspected semiconductor wafer from the inspection section and returns it to the wafer carrier.
Upon reception of a semiconductor wafer from the loader section, the inspection section first performs either macro inspection or micro inspection with respect to the semiconductor wafer.
It should be noted, however, that uninspected semiconductor wafers stored in the wafer carrier are not aligned with one another. In other words, the loader section takes them out as they are, and delivers them to the inspection section. As a result, the centers of the semiconductor wafers received by the inspection section are shifted from one another.
Normally, the semiconductor wafers are centered before they are delivered to the inspection section.
A non-contact sensor, such as that disclosed in Jpn. Pat. Appln. KOKAI Publication No. 11-243129, is used for centering the semiconductor wafers. The non-contact sensor includes a light-emitting section and a light-receiving section between which a semiconductor wafer is inserted. This type of sensor is used because it does not damage the semiconductor wafer or generate dust.
In a photolithography step included in the manufacturing process of semiconductor devices, the surface of a semiconductor wafer is examined to detect a defect, such as a scratch, a crack, a stain, or an uneven surface portion. In recent years, it is important to detect if dust attaches to an edge portion of a semiconductor wafer, if a crack is present, and the state of the width of a cut (i.e., removed portion) in a photoresist is, because the detection of these is a significant measurement item in terms of the prevention of a defect in the subsequent steps.
In the inspection of the edge of a semiconductor wafer, a light source used for illuminating a wafer edge portion and a video camera used for detecting a defect at the edge portion are arranged at positions away from each other, as disclosed in Jpn. Pat. Appln. KOKAI No. 2000-136916.
The aforesaid non-contact sensor and image sensor for the edge portion detection are provided inside the substrate inspection apparatus. Therefore, they must satisfy the requirements, such as a reduction in size, a small installation space and a low-manufacturing cost.
Accordingly, an object of the present invention is to provide an imaging device which is small in size, can be installed in a small space, is compact, and can be manufactured at low cost.
The present invention provides an imaging device comprising: an LED light source which emits a laser beam; an optical path-splitting element located on an axis of light emitted from the LED light source; a collimate lens located on one of optical paths of the optical path-splitting element and collimating the laser beam output from the LED light source; and a two-dimensional imaging element located on another one of the optical paths and performing an image-pickup operation with respect to the reflected light guided from the collimate lens and converged by the collimate lens.
The imaging device of the above configuration is small in size, requires a small installation area, is compact and can be manufactured at low cost.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.